Fonts

I have a variety of fonts both from installing XP Pro and the various programs. Is there a way of finding out which fonts are really required by a program for it to work properly and those just installed as extras but not actually required.

If you want to manage unused fonts consider that you can't delete or replace system fonts in WndowsXP, you either get an access denied or Windows will replace them after you remove them so you shouldn't be able to cause any damage.
Gets difficult to say what third party program use what kind of fonts...
For sure adobe programs install and use proprietary fonts with extensions PFB and PFM (not the usual TTF)